Uniform and low-speckle illumination with a 1D on-chip phased array and multimode fiber

Speckle degrades performance in metrology, holography, and tomography. While mechanical diffusers or 2D optical phased arrays suppress speckle, they demand bulky mechanics or complex two-plane routing. We present a simpler, all-integrated solution: a 1D OPA edge-coupled to a multimode fiber. In this research, we assessed the best design of the OPA to mimic the uniform illumination of the 2D OPA and derived a closed-form contrast model, which was verified numerically. Combined with spectral or polarization diversity, the scheme enables compact, vibration-free sources with a speckle contrast of 0.01.